The following are co-pending applications in the same field showing the state of the art which are herein incorporated by reference:
1. Robot Calibration, Ser. No. 06/453,910, now abandoned. PA1 2. Electro-Optical Systems for Control of Robots, Manipulator Arms and Coordinate Measuring Machines, or "Robots and Manipulator Arms", Ser. No. 592,443, filed Mar. 22, 1984, now U.S. Pat. No. 4,602,163. PA1 3. Robot Tractors Ser. No. 06/323,395, now U.S. Pat. No. 4,482,960. PA1 4. Robot Tractors, Vehicles and Machinery, Ser. No. 651,325, filed Sep. 17, 1984, now U.S. Pat. No. 4,769,700. PA1 5. Electro-optical sensor systems for thread and hole inspection Ser. No. 06/064,867, now U.S. Pat. No. 4,315,688. PA1 6. Method and apparatus electro-optically determining the dimension, attitude and location of objects: Ser. No. 06/034,278. PA1 7. Method and apparatus for determining physical characteristics of object and object surfaces: Ser. No. 06/015,792, now U.S. Pat. No. 4,373,804. PA1 8. New photodetector array based optical measurement systems: Ser. No. 06/163,290, now U.S. Pat. No. 4,394,683. PA1 9. Electro-optical inspection, Ser. No. 06/073,226, now abandoned. PA1 10. Co-ordinate measuring method and device, Ser. No. 06/201,081, now abandoned. PA1 11. Electro-optical sensors with fiber optic bundles, Ser. No. 06/173,370, now U.S. Pat. No. 4,441,817. PA1 12. Electro-optical surface roughness measurement and control Ser. No. 06/240,459, now abandoned. PA1 13. Apparatus for determining dimensions, Ser. No. 06/134,465, now U.S. Pat. No. 4,403,860. PA1 14. High speed electrooptical inspection, Ser. No. 06/203,866, now abandoned. PA1 15. Fiber optic based robot controls, Ser. No. 06/200,401, now U.S. Pat. No. 4,460,826. PA1 16. Electro-optical sensors for machine tool and robotic inspection, Ser. No. 06/247,399, now abandoned. PA1 17. Electro-optical systems for control of robots, manipulator arms and coordinate measurement machines Ser. No. 06/262,497, now U.S. Pat. No. 4,453,085. PA1 18. Method and apparatus for determining wear or breakage of tools and other defects, Ser. No. 06/323,397, now U.S. Pat. No. 4,420,253. PA1 19. Electro-optical systems for detection of leakage and blockage, Ser. No. 06/323,399, now abandoned. PA1 (a) The general concept of use of such `active` lighting in automation and particularly the use of fibers therefore. PA1 (b) The use of `active detection` wherein the light is directed from the robot into one end of a fiber, and sensed at the opposite end of said fiber. PA1 (c) The use of other materials than fibers, for example, translucent fixtures of Teflon or ceramic. PA1 (d) The use of multiple target points on the illuminated piece to be tracked. PA1 (e) The use of blow-offs to keep the targeted fixtures clean. PA1 (f) The use of pulsed or modulated light sources discrimination against background noise. PA1 (g) The use of light sources and electro-optical sensors both located on robot where the light source of the robot is directed to a predicted entrance point of the fiber(s) and the light emanating from the opposite end of the fiber(s) is sensed by the camera of the robot. Two robots for example could be used, one to light the part or fixture, the other to sense it.
Flexible robot assembly is often very difficult in the absence of machine vision sensors to guide the operation. Even with such sensors, operation must be both accurate, ultra reliable, and fast enough to be justifiable relative to human labor. These criteria are seldom met by present day vision systems employing arbitrary gray level images and the like.
The target based invention described in reference 1 above has wide application to the assembly process. Described therein are several embodiments illustrating target based techniques which can overcome the limitations of present systems. The key to the use of the disclosed systems is that the target points on the part are easily discernable and unambiguous, after processing using rapid devices and other high speed analysis software.
The target system functions well because it is based on high contrast images and mathematical equations. To use targets one must know the part feature data base relative to the target points on the part. Targets on tooling, pallets and fixed members may also be of use. Special retro reflective targets give best contrast, but targets can be holes, corners or other easily determined natural part features.
Finally, where special targets are used which would not normally be present, techniques are disclosed to make these unobtrusive.